One of the hottest tickets in Los Angeles this month was for a last-minute club show by Atoms for Peace, the high-profile side project built around an odd couple of alternative-rock superstars.

The concert was in preparation for an extensive world tour that Radiohead frontman Thom Yorke and Flea of Red Hot Chili Peppers were to launch in the wake of their debut, the February release "Amok." The idea was to try out some of the Atoms material in front of a small audience at a cozy West Adams performance space temporarily dubbed Club Amok.

Those left without passes (distributed in part by radio stations and independent record stores) lodged the usual complaints on Facebook and Twitter, and for good reason, as it turned out. The gig was excellent: two hours of detailed, propulsive art rock.

But any Angeleno who wanted to check out the band's progress could have if he or she had only known where to look. For several weeks before the show Atoms for Peace — which also includes drummer Joey Waronker, percussionist Mauro Refosco and multi-instrumentalist Nigel Godrich — could easily be heard rehearsing at a mansion owned by producer Rick Rubin on Laurel Canyon Boulevard just south of Mulholland Drive.

That sprawling home is where the L.A.-based group was running through its song "Default" recently, front doors flung wide open, the sound of Flea's anxiously ascending bass line drifting down to the street as cars crawled by.

"There's a lot of figuring out to be done," Yorke said during a break, seated with Flea on a patio of the house, believed to have once belonged to Harry Houdini. The singer's long hair was tucked beneath a baseball cap, and a number of bracelets encircled his wrist; Flea's tattoos peeked out from under the sleeves of a T-shirt. "Just getting the levels, the mechanics of the melodic ideas and the beats, and then trying to ease into the grooves and figure out what sounds to use…" Yorke trailed off. "It takes time."

With Atoms for Peace, it always seems to. Assembled as a means of performing the twitchy, computer-born songs from Yorke's 2006 solo album "The Eraser," the band made its live debut in late 2009 with instantly sold-out concerts at the Echoplex and the Orpheum Theatre.

The next year it went on the road, appearing at the 2010 Coachella Valley Music and Arts Festival, then used that experience onstage to create new tracks, which Yorke and Godrich meticulously rebuilt in the studio for "Amok." (A producer known for his work with Beck and Paul McCartney, Godrich has overseen the recording of every Radiohead record since 1997's creative breakout "OK Computer.")

Now, at Rubin's mansion in the run-up to the tour set to begin July 6 in Paris, Atoms for Peace was converting those precisely rendered productions back into real-time music.

"You'd think it would be simple because, technically speaking, we've played all these songs before," Yorke said with a wry chuckle. "But it's not. The way Nigel and I chopped everything up and rearranged it, a lot of the stuff on the album is unrecognizable even to the people who originally played it."

It's an approach that speaks to the increasingly fluid relationship between the studio and the stage. Driven to experiment during production by the endless possibilities of digital recording technology, many bands are no longer content (or no longer able) to simply replicate their albums in concert; whether by choice or necessity, the live setting has become an opportunity to "reinterpret what happened in the studio," as Waronker put it. "You put all this work into making the record, but then it's static," the drummer said. "Whereas when you're playing live, you have to realize it differently every night. That's exciting."

At its warm-up show this month, Atoms for Peace — scheduled to stop at the Hollywood Bowl on Oct. 16 and the Santa Barbara Bowl on Oct. 17 — sounded funkier and harder-edged than it does on "Amok," with more muscular guitar action and more intense rhythmic momentum. And it roughed up sleek electronic tunes from "The Eraser" such as "Skip Divided," which had Flea headbanging as he tootled on a melodica, and "Harrowdown Hill." The latter got so furious, in fact, that Yorke appeared to fall down at one point.

"Every day is full of little triumphs," Flea said of the rehearsal process, which involved transposing stitched-together melodic lines for live instruments and figuring out how to play programmed beats by hand. "And every time we come across a successful interpretation, I look around the room and see everyone gone in this groove, feeling the spirit. It's such a beautiful moment."

The bassist's wide-open SoCal vernacular is a reminder of how different he seems from Yorke, the reserved Englishman known for his mumbly vocals and his cryptic lyrics about government malfeasance. The two teamed after Yorke (who said he'd always wanted to play with Flea) began spending a considerable amount of time in L.A., itself a seeming contradiction given his general aversion to the celebrity-industrial complex.

"I spent 17 or 18 years coming here [with Radiohead], staying in West Hollywood at the Chateau Marmont to various degrees of decadence," he recalled. "And then eventually I got pulled out of that and started going to friends' houses further east and went, 'Wow, there's something about this place — it makes me happy.'" He'd fallen in with members of the Eastside's so-called beat scene (such as Flying Lotus and the Gaslamp Killer), and forming Atoms for Peace gave him a reason to stick around.

The work since has narrowed the apparent gap between Flea and Yorke, according to Waronker, a longtime L.A. session drummer who has also played with Beck and R.E.M. (Refosco has toured as a percussionist with Red Hot Chili Peppers and David Byrne, among others.) "I never would've called it, but it actually couldn't be a more perfect union," Waronker said.

Talking at Rubin's house, the two struck common ground when the conversation turned to the dancing onstage. Anyone who's seen the Chili Peppers play knows that Flea earned his nickname long ago. "The way I move my body is how I feel the groove," he explained. Yet it's been surprising over the last few years to watch the once-stoic Yorke grow into a similar physicality: "I've become more like that, as well," he said to Flea.

In 2011 the video for Radiohead's song "Lotus Flower" — from that band's most recent album, "The King of Limbs" — went viral thanks to Yorke's idiosyncratic moves, and onstage at Club Amok he flailed his arms with impressive abandon.

"That's one of the best things about this band," he said, "the idea that you can take something electronic — something that exists on a screen — and you can re-create it as a physical experience. It can be quite…," he trailed off again, as though searching for the right phrase. "It can be quite a sexy thing."